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Carpal tunnel syndrome is the most common compression lesion of peripheral nerves with a prevalence of 4%. It is often treated by release of the flexor retinaculum, which may completely relieve the symptoms. Although such treatment is considered successful, there are probably many patients with persistent or recurrent symptoms. Recurrence implies that the patient's symptoms were initially relieved but recurred some time after the operation; this is a controversial field in which clear definitions, aetiology, diagnosis, and treatment seem uncertain. We describe recurrence of carpal tunnel syndrome and summarise possibilities for diagnosis and treatment of the condition.

Clinical assessment and various diagnostic tools, particularly magnetic resonance imaging (MRI), of tumours of peripheral nerves are used to get an accurate diagnosis and to plan surgical intervention. Our purpose was to examine the usefulness of MRI in assessing nerve tumours in the upper extremity. Medical records of 19 patients (20 MRI examinations) with 29 histopathologically verified benign nerve tumours were examined retrospectively. In 12/20 cases MRI suggested a correct diagnosis of the type of nerve tumour. An additional 3/20 cases had an uncertain diagnosis, but nerve relations to the tumour were established. In 5/20 cases MRI gave a doubtful diagnosis with no suspicion of the tumour being located in a nerve trunk. MRI can localise and diagnose a nerve tumour in the upper extremity in 75% of cases, but it is difficult to specify the type of tumour.

Peripheral nerve tumours are uncommon. Our aims were to calculate the incidence and relative frequencies, to define sites of nerve tumours and to judge preoperative symptoms and outcomes of intervention. The results of 53 patients, with 68 tumours and histopathological diagnoses of true neoplasms, who had been operated on at the Department of Hand Surgery, Malmo, Sweden, between 1986 and 2007, were analysed. Schwannomas were the most common tumour (n=42). The incidence of schwannomas was 0.62/100 000 inhabitants/year in Malmo during that time period. The median nerve was most affected, closely followed by the ulnar and digital nerves. The preferred sites were the forearm, the thumb, and the digits. The most common preoperative symptom was pain. Loss of sensation was the most common postoperative complication. However, 33/53 patients (62%) were completely free of symptoms after excision. Patients should be provided with meticulous information preoperatively.

Two neonates with proximal dorsal swelling and skin necrosis had median, ulnar, and particularly radial nerve palsies after birth, which was interpreted as compartment syndrome in the forearm. The swelling in case 1 disappeared, the skin lesion in case 2 healed, and the functions of nerves recovered almost completely in both cases, although the forearm and hand in the second patient were shorter and thinner than the contralateral side.

Fourteen children (median age 43 months, range 14-82 months; 7 girls and 7 boys) were treated for mangle injuries (one hot steam, and 13 cold roller presses) to the hand and forearm between 1996-2002 at the Department of Hand Surgery, Malmö, Sweden. All children had unilateral skin damage with avulsion or necrosis of skin in nine. Seven of the 14 had signs of compartment and carpal tunnel syndromes and three had fractures (phalanges or hamate bone). Initial treatment included fasciotomy, decompression, and skin revision with split skin grafts and later further skin cover, including one pedicled ulnar flap. IN eight the injuries healed uneventfully, while six had slight consequences (such as minor extension deficit of fingers or slight contracture of the scar). Ten of the 14 children came from immigrant families. Mangle injuries can be prevented through better supervision of children by parents when the mangle is being used, and dissemination of information of the potential hazards in relevant languages in residential areas with large immigrant populations.

Cultured Schwann cells in tendon autografts for nerve repair improve the early phase of nerve regeneration in rat sciatic nerves as judged by the rate of axonal outgrowth. We tested the long-term effects on functional recovery using measurements of muscle force, the number of axons and myelination, using morphometry. In addition, we recorded wet weight of the gastrocnemius muscle. Schwann cell cultures were prepared from predegenerated nerves. Ten and 15 mm defects in rat sciatic nerves were bridged using bilateral tendon autografts with Schwann cell-seeded tendon autografts on one side, and untreated tendon autografts on the other. Animals were evaluated at six and 12 weeks, respectively. At six weeks, myelination, as judged by G-ratio (ratio of axonal diameter to diameter of nerve fibres), was significantly increased in tendon autografts pretreated with Schwann cells in 10mm defects. No such difference was seen in the 15 mm defects. We found no difference in functional recovery, other morphometric variables, or muscle weight between the two grafts. We conclude that early effects on nerve regeneration using transplantation of cultured Schwann cells in rat sciatic nerves are temporary. Other strategies are necessary to obtain lasting effects on functional recovery.

We describe a patient in whom the motor branch to the first dorsal interosseous muscle was injured by the pins of an fixator used to treat an unstable fracture of the distal radius. She was successfully treated by extensor indicis proprius transfer to the base of the proximal phalanx of the index finger.

We describe two patients with uncommon causes of iatrogenic injuries and review the anatomy, presentation, possibilities of repair, and results. The incidence of such nerve injuries during lymph node biopsies is 3%-10%, but the diagnosis is often delayed. Symptoms are shoulder pain and inability to abduct the arm beyond the horizontal plane. Surgical repair may improve function and pain and should be performed early, preferably within six months, but prevention of nerve injury is most important.

The radial nerve may not function in association with fractures of the humeral shaft. There are various opinions about the causes and treatment. We report a case of complete rupture of the radial nerve after a fracture of the proximal shaft of the humerus. The nerve injury was treated with grafting and TENDON transfer. Here we discuss diagnoses and treatments including neurobiological aspects of nervous regeneration. We suggest that electrodiagnostic examination after a radial nerve palsy caused by a humeral fracture is done 5-6 weeks after injury and that nerve repair and reconstruction should be done within two, and not later than three, months after injury.

Partial and complete injured median and ulnar nerves caused by fractures of the radius and ulna, respectively, in which the symptoms of nervous injury were induced at the time of fracture are reported. In cases with complete loss of nervous function early exploration should be considered at the time of reposition or plating of the fractured bones, or both, and in patients in whom nervous dysfunction occurs after the operation.

Staining by activating transcription factor 3 (ATF3), a neuronal marker of nerve injury, was examined by immunocytochemistry in neurons and Schwann cells after crush or transection (regeneration inhibited) of rat sciatic nerve. ATF3 immunoreactivity peaked in neurons after three days and then gradually subsided to normal within 12 weeks after the crush. The response lasted somewhat longer and declined over time in spinal cord neurons but not in those of dorsal root ganglia (DRG) after transection, indicating a differential regulation of sensory and motor neurons. ATF3 expression was more pronounced in Schwann cells, and remained longer after transection, implying that to some extent regenerating axons produce signals that reduce ATF3 expression in Schwann cells. However, even after transection without repair (no contact with regenerating axons), ATF3 expression in Schwann cells in the distal segment decreased over time suggesting that regenerating axons are not entirely responsible for the down-regulation. These findings have clinical implications on when it is worthwhile to reconstruct nerve injuries.

Ninety-six children aged 0-6 years with unintentional hand injuries were referred to the Department of Hand Surgery between 2002 and 2003. Either parents, medical staff, or both, completed a questionnaire (response rate 79/96; 82%) about the circumstances of the injury. The incidence of injuries referred for treatment was 33.4/10,000 people/year. Seventy-five percent (59/79) of all injuries occurred at home, and only 8% (6/79) in a day-care centre. The risk was highest between 4 p.m. and 8 p.m. (incidence rate ratio 5.17, 95% confidence interval 2.12 to 17.7) and in 6 year old children (IRR 4.89, 95% CI 1.58 to 37.68). Adults were present when 66/79 children (84%) were injured. Most injuries occurred during play (39/79; 49%). Stuck in front doors (23/79; 29%) (closed by a child) was common. There was no increase in incidence in children with a foreign background (IRR 1.19, 95% CI 0.64 to 2.28). Advice about prevention will be distributed to parents to encourage safer environments in homes.

Regeneration occurs if a distal nerve segment is attached end-to-side to an intact donor nerve after the nerve has been injured. We investigated if attachment of a proximal nerve segment as well, as an extra source of axons, had any advantage over the single attachment of a distal nerve segment to the same donor nerve. In rats, a single distal radial nerve, or both the proximal and distal radial nerve segments, were attached end-to-side to the musculocutaneous nerve, and effects were examined up to eight months after the repair. Cell profiles were double-labelled, indicating recruitment of axons by collateral sprouting, but there were few such cells. There was a shift in the distribution of retrograde labelled neuronal cell profiles in spinal cord and in DRGs between the two types of repair. Both procedures resulted in axonal outgrowth and some functional recovery, but there was no improvement if a proximal nerve segment was also used as a source for axons.

We wanted to find out if any of three different types of manipulations: a piece of muscle or nerve put parallel to a nerve; an epineurial window made, or sutures inserted into a nerve, or both; or pieces of nerve sutured to an epineurial window end-to-side to the musculocutaneous or sciatic nerve, resulted in activation of activating transcription factor 3 (ATF3) in neurons and in non-neuronal cells. ATF3, a marker of cell activation, was investigated by immunocytochemistry one week after manipulation. A piece of nerve or muscle parallel to a nerve did not induce ATF3 locally in the nerve and induced ATF3 only rarely in neurons. In contrast, an epineurial window or insertion of sutures, or both, with or without attachment of a piece of nerve placed end-to-side, induced robust ATF3 expression. We conclude that an injury to a peripheral nerve trunk associated with end-to-side nerve repair, activates neurons and non-neuronal cells and may contribute to sprouting of axons into the nerve attached end-to-side.

An axillary brachial plexus nerve block by a transarterial approach is commonly used to achieve regional anaesthesia for hand surgery. We designed a retrospective study to evaluate efficacy and safety of the technique for acute and elective operations. Anaesthetic records of 189 of all 5520 patients (1996-2000) who had axillary brachial plexus blocks for hand surgery were reviewed, and results compared with complications recorded in the anaesthetic register and in the hand surgery records. Successful axillary block was achieved in 5128/5520 (93%) of patients, according to anaesthetic charts, and primarily in 157/189 (83%), and after supplementation in 171/189 (90%), according to anaesthetic records. Four patients had a toxic drug reaction or axillary haematoma with a transient neurological deficit. Medical complications were recorded in the anaesthetic register in less than 0.7% of axillary brachial plexus procedures. Axillary brachial plexus block by a transarterial approach is effective and safe in hand surgery.

A-36-year-old man presented with classic symptoms of a glomus tumour in the right index finger that failed to show on either ultrasound or high resolution magnetic resonance imaging (MRI). The radial finger pulp was explored despite the radiological findings and a glomus tumour 2 mm in size was excised. At follow-up the patient was pain-free. We conclude that exploration of an affected fingertip should be considered when there is a history of suspected glomus tumour even if MRI shows no sign of disease.

Patients with injured hands and forearms of varying severity [Hand Injury Severity Score (HISS)] were studied prospectively, including analysis of costs, hand/arm function (DASH), and health status (SF-36). Costs, duration of sick-leave, DASH-score (high score; impaired function) increased by severity of injury (higher HISS) and the greatest proportion of total costs resulted from lost production. Most employed patients returned to work within a year, but even minor injuries were expensive. HISS and costs of care during an emergency were significantly associated with duration of sick-leave, although HISS did not fully explain variation in costs and duration of sick-leave. DASH-score at one year was associated with variation in age, HISS, and residual health care costs. Results of DASH and subgroups for physical and bodily pain on SF-36 were consistent. Injuries to hand and forearm may generate high costs for society in terms of health care and long periods of sick-leave (lost production), but even minor injuries should be accounted for.

A new method of acute dissociation of Schwann cells was used to study the effect of addition of such cells to a tendon autograft--a recently-described graft material--on peripheral nerve regeneration in rats. Autologous Schwann cells were obtained from enzymatic dissociation of predegenerated nerves. The tendon autografts were supplied with Schwann cells through brief in vitro coincubation. Schwann cell-free tendon autografts were used as controls. Axonal outgrowth was measured immunohistochemically after four, seven, and 10 days. At seven days, outgrowth was significantly longer in the pretreated autografts. The use of acutely-dissociated Schwann cells is a new approach to tissue engineering in nerve reconstruction, and may abolish the need for time-consuming culture of Schwann cells.

Nuclear translocation of activating transcription factor 3 (ATF3), used as a marker for neuronal injury, was studied by immunocytochemistry in sensory neurons in dorsal root ganglia and locally along the sciatic nerve after severe chronic nerve compression in rats. In compressed nerves (application of a narrow silicone tube), ATF3 immunoreactivity was seen in the nucleus of sensory neurons and in Schwann cells below the compression at two and four weeks. Removal of the silicone tube (decompression) at two weeks did not affect the number of ATF3-positive cell nuclei in dorsal root ganglia. No ATF3 immunoreactivity was found in undamaged nerves on the other side. Functional variables (toe spreading and muscle force) were impaired at two weeks, with partial improvement at four weeks. Nerve compression induces nuclear translocation of ATF3, a transcription factor associated with survival and regeneration of sensory neurons. The response is related to duration of compression and partly correlated to function.

We describe a case of bilateral congenital hypoplastic finger pulps of the little finger in a 6-year-old girl in whom reconstruction with a neurovascular step-advancement flap was used to restore soft tissue padding of the pulps.

Case notes of patients with hand injuries that required referral to our department in 1989 and 1997, were analysed retrospectively. The incidence of such an injury was at least 7/1000 inhabitants/year (12% of the patients seen in the orthopaedic Accident and Emergency department). Most of the patients were young men with minor injuries, most commonly injured during leisure activities. Only 22% of the patients who worked were injured at work, but such injuries increased the risk of admission to hospital. The amount of sick leave was significantly shorter in 1997, and 77% of the workers were off work for less than two months. There was a reduced risk of injury during July, November, and December, and on Tuesdays. Type and range (type/mechanism/severity) of injuries differed slightly between the years and among the various age groups. Epidemiological data about hand injuries that affect young patients of productive age, are important to optimise resources and organisation of the health care system.

The functional recovery was examined after two different methods had been used to bridge an extended nerve gap. A 15 mm defect in the rat sciatic nerve was repaired using a tendon autograft--a new graft material--on one side and a freeze-thawed muscle graft--a well established experimental material--on the other side. Evaluation after 12 weeks included measurements of tetanic force in the gastrocnemius muscle and computerised morphometry of the tibial nerve. The muscular tetanic force recovered to 26% and 21% of control muscles, respectively, but there were no significant differences between the two types of grafts in any of the measurements. The number of regenerated axons of the tibial nerve correlated with functional recovery as judged by muscular tetanic force in the gastrocnemius muscle. We conclude that the tendon autograft supports functional recovery, as judged by return of muscular tetanic force, to an extent comparable to that of the freeze-thawed muscle graft.

Granular cell tumours in peripheral nerve trunks are extremely rare. We report a case of a granular cell tumour of the ulnar nerve just distal to the elbow in a 16-year-old man. The appearance of the intraneural tumour could not be differentiated by magnetic resonance imaging (MRI) from more common nerve tumours. At exploration it was impossible to excise the tumour radically. Microscopic examination showed a clearly benign tumour and no malignant transformation has been found at follow-up after three and a half years.

Fifteen patients (10 women and 5 men; median age 46 years; range 28-55), with recurrent severe carpal tunnel syndrome, were operated on with re-exploration and cover of the median nerve with free or pedicled flaps (five pedicled ulnar flaps, one pedicled dorsal forearm flap (served by the posterior interosseus artery), one groin flap, three free scapular flaps, and five free lateral arm flaps). The patients were followed up by a self-administered questionnaire at 3 months-14 years (median 8.5 years) after operation and replies were obtained from 14 patients. There was a significant improvement in pain (p = 0.01) and percussion tenderness at the wrist (p = 0.02), but no significant improvement in allodynia and cold intolerance in the hand as evaluated by the use of a visual analogue scale (VAS). Three of the 14 patients had less numbness/paraesthesiae and four had subjectively improved sensory function in the hand and fingers since the procedure. Ten patients had problems from the donor site, including a cosmetically unacceptable scar, allodynia, and itching. Four patients had worked before the operation and nine patients returned to ordinary or light work afterwards. In conclusion, 10/14 patients considered themselves as somewhat better, better, or cured, while four felt that they were unchanged or worse. We conclude that cover with vascularised fat may be worthwhile in some patients with recurrent severe carpal tunnel syndrome, preferably with a simple pedicled ulnar flap.

Nerve regeneration, measured as axonal outgrowth, Schwann cell migration, macrophage invasion, and neovascularisation, was compared after repair of a 15 mm gap in rats' sciatic nerves using autologous muscle grafts made acellular either by freezing and thawing or by chemical extraction. Both extracted and freeze-thawed acellular muscle grafts could be used to bridge the defect. However, axons and Schwann cells, as shown by immunohistochemical staining for neurofilaments and S-100 protein, respectively, grew faster into the extracted muscle grafts than into the freeze-thawed acellular muscle grafts and somewhat more axons were observed in the former graft. There were no significant differences between the two graft types with respect to neovascularisation as showed by staining for endothelial alkaline phosphatase, and limited differences concerning invasion of macrophages (ED1 and ED2) as detected by immunocytochemistry. The results showed that chemically extracted muscle grafts could be used to bridge an extended nerve defect and that such grafts in some aspects were superior to freeze-thawed muscle grafts for extended gaps.

We studied regeneration distance of rat sciatic nerve, with the sensory pinch reflex test and immunocytochemical staining for neurofilaments, four to 21 days after transsection, repair, and enclosure of the repair site in either a non-absorbable silicone tube or an absorbable polyglycolic acid (PGA) tube. The size of both tube-types was carefully selected so that they did not compress the repaired nerve. The opposite nerve was repaired and not inserted in a tube (control). The regeneration distances in repaired nerves enclosed in silicone tube were significantly longer than the control side at all time points, a result not seen when PGA tube was used. The number of proliferating non-neuronal cells (incorporation of 5-bromodeoxyuridine (BrdU)) was studied just proximal to the site of nerve repair after six days. Numerous stained cells were seen, but there where no significant differences between the groups. We conclude that outgrowth of sensory axons after transsection and repair of rat sciatic nerve with sutures can be increased by enclosing the site of repair in a silicone tube but not in a PGA tube. The effect is probably not related to the number of proliferative non-neuronal cells.

A substantial number of people who are exposed to vibrating hand-held tools develop vasospastic and sensorineural symptoms that may seriously affect the ability to work. Apart from the discomfort of the disease itself, this leads to socioeconomic problems for the patients and high costs for the society. The diagnosis of the neurological symptoms is sometimes difficult and may be misinterpreted as a nerve compressive disorder such as carpal tunnel syndrome, which may also develop. This review summarises our available knowledge about the pathophysiology of the neurological dysfunction with reference to hand problems after exposure to vibrating hand-held tools.

We studied the effect of hyperbaric oxygen treatment on axonal outgrowth in grafts of sciatic nerves in 40 rats. The sciatic nerve was transsected and a 10 mm long segment from the opposite side was immediately sutured in as a nerve graft. Postoperatively 17 animals were treated with 100% oxygen at 3.2 atmospheres absolute pressure for 45 minutes and the treatment was repeated at four and eight hours postoperatively and then every eight hours until evaluation. At seven days the axonal outgrowth was evaluated by immunohistochemical staining of neurofilaments in the nerve grafts. The axonal outgrowth was significantly longer in animals treated with hyperbaric oxygen. We conclude that hyperbaric oxygen can improve nerve regeneration in sciatic nerve grafts in rats.

Silicone tubes of appropriate sizes were used to enclose the injured zone of transsected ulnar and median nerves in the human forearm as an alternative to conventional microsurgical repair of the nerve trunk. A gap measuring 3-5 mm was left intentionally between the nerve ends inside the tube. The clinical early results from a prospective randomised study that compared these two principles have recently been presented. Seven patients (five men and two women), aged 15-49 years (median 20) were reexplored 12-44 months (median 22) after the initial procedure because of local discomfort from the tube in four patients. There was a new nerve structure bridging the former gap and in most cases it was impossible to distinguish the site of the injury. In all cases there was a thin capsule around the silicone tube that microscopically consisted of connective tissue with thin walls and no signs of inflammation, granuloma or macrophages (n = 4), while in two cases a mild foreign body reaction was seen at a single site (n = 1) or at patchy areas (n = 1). These results indicate that after more than one year there is a limited tissue reaction around silicone tubes used to repair median and ulnar nerves in humans.

A long defect (15 mm) in rat sciatic nerve was repaired with a bioartificial nerve graft composed of a silicone tube and seven synthetic filaments of five types (polyamide, catgut, polydioxanone, and two types of polyglactin, normal and quickly-absorbed) inserted longitudinally into the tube. In all cases in which filaments were used a regenerating bridge was obtained in the tube after three months in contrast to empty silicone tubes, in which no structure was observed. There was a 6%-46% recovery of isometric muscle contractility of the anterior tibial and gastrocnemius muscles with positive pinch reflex test in most cases. Myelinated axons were seen in the regenerating tissue between the filaments but not directly in contact with them, and there were varying numbers of macrophages close to the filaments. Silicone tubes with filaments, regardless of type of filament, induced nerve tissue to regenerate and resulted in functional recovery through a 15 mm nerve gap not achieved with empty tubes. Nerve promoting factors may be applied to the filaments and the model is a valuable tool for further development of artificial nerve grafts.

We have proposed that it is sufficient to provide a simple substratum on which regenerating axons may traverse a gap in a peripheral nerve. To test this hypothesis we set up a new experimental model in which sutures were used to bridge a 10 mm long defect in a peripheral nerve. A defect was created bilaterally in 25 rat sciatic nerves. The cut ends of the nerve were joined by three laps of a continuous suture, on one side with 8/0 polyamide (non-absorbable) and on the other with 8/0 polyglactin (absorbable), leaving a 7 mm gap. At two weeks a matrix that contained capillaries, fibroblast-like cells, and mononuclear cells had formed between the nerve endings, and the sutures were surrounded by foreign-body-like tissue reactions. At four weeks axons had grown into the distal nerve segment on both sides in 65%-90% of the cases as indicated by a response to the pinch reflex test and immunocytochemistry for presence of neurofilament protein. Axons were organised in minifascicles and these tended to grow larger as the demarcation of the entire regenerated segment by a perineurial-like structure improved with time. At 12 weeks axonal counts of cross-sections of the distal tibial trunk showed many myelinated nerve fibres but no significant difference in axonal counts or degree of myelination between the polyamide and polyglactin sides. The results show that conventional sutures alone are sufficient to support regeneration across a short gap in a peripheral nerve, a method that may be of potential clinical value.

To investigate the temporal changes in the results of clinical tests of the functional outcome after nerve repair, we followed up 19 patients periodically over a four year period after repair of the median or ulnar nerve at the forearm. Between the first and last follow-up four of the instruments used--Semmes-Weinstein monofilaments, manual muscle testing, Sollerman grip test, and Jamar dynamometer--indicated significant and moderate to large improvements. A moderate and significant improvement was also noted during the same period in patients' estimation of pain or discomfort. Results of the two-point discrimination test did not change significantly over time. Most changes occurred during the first postoperative year, and thereafter it was principally motor function that improved. We conclude that four of the six used tests showed useful temporal dynamics during the follow-up time. The lack of responsiveness in two-point discrimination test suggests that other or complementary test instruments should be used for assessment of tactile gnosis after nerve repair.

Application of granulation tissue, which is rich in macrophages, to a peripheral nerve induces a conditioning effect, in that it enhances the regeneration capability of peripheral nerves after a test crush lesion. The temporal aspects of this response and the role of macrophages and interleukin-1 beta (IL-1 beta) were studied in the sciatic nerves of 71 rats. Granulation tissue was implanted close to the sciatic nerve and test crush lesions were applied after various periods of time (0-21 days). Regeneration was evaluated after an additional two, three, four, or six days. Regeneration distances were longer in granulation-treated nerves than in nerves treated with subcutaneous tissue. Furthermore, in animals in which the test crush lesion was made at the same time as the granulation tissue was implanted (n = 6), regeneration distances were longer, 8.1 (0.8) mm compared with 7.2 (0.6), than those in which the crush was made after conditioning intervals of 3 (n = 6, 7.6 (0.4) compared with 6.9 (0.4), p = 0.03); 7 (n = 6, 7.4 (0.4) compared with 6.6 (0.1), p = 0.03); and 21 days [(n = 8, 7.2 (0.6) compared with 6.4 (0.5)]. Inactivation of the granulation tissue by freezing suppressed the conditioning effect. There were numerous ED1 and ED2 positive macrophages as well as positive staining for IL-1 beta in the granulation tissue on day 0. Positive staining for IL-1 beta was also seen in nerve fibres as well as in non-neuronal cells after a conditioning interval. The results suggest that regeneration is stimulated by factors released from the cells of the granulation tissue, and that the amount of factors released or the responsiveness of the regenerating nerve change during the conditioning interval.

The perception thresholds for vibration stimuli of the hand at seven frequencies (8-500 Hz) were evaluated in 300 patients referred to the Department of Hand Surgery in Malmö during the years 1985-1990 for various types of neuropathy (carpal tunnel syndrome, vibration-induced neuropathy, cervical rhizopathy, brachialgia, ulnar neuropathy, radial tunnel syndrome, and polyneuropathy). A sensibility index was calculated by dividing the integrated area under the obtained vibrogram curve of each object tested (areaT) by that of the corresponding area under a superimposed and age matched reference curve (areaR). Sensibility index of less than 0.8 was regarded as the cut off value. The index and little fingers bilaterally were tested to reflect median and ulnar nerve function. There were considerable variations in patterns of pathology among the various groups of patients. In patients with unilateral carpal tunnel syndrome only 10 patients (23%) had abnormalities limited to one recording, while 21 patients (47%) showed abnormalities in all four recordings. This indicates that an isolated carpal tunnel syndrome may reflect more generalised disease of the peripheral nervous system.

The effects of application of a chromic catgut suture (conditioning lesion) placed close to the sciatic or tibial nerves on regeneration of the sciatic nerve after a crush lesion (test lesion), that had been induced after an appropriate conditioning interval (two or four weeks) were assessed. The catgut suture induced an inflammatory reaction around the nerve during the four weeks after application of the catgut suture (conditioning interval) but no signs of degeneration of nerve fibres were seen. There was a significant increase in length of outgrowth of sensory nerve fibres as measured by the pinch reflex test when the test lesion was applied after two and four weeks' exposure to the catgut suture. The rate of regeneration was increased by about 11% when the catgut suture had been applied for four weeks before the test lesion was made. The findings indicate that an inflammatory reaction around a peripheral nerve may act as a conditioning lesion, thereby stimulating regeneration of the nerve.

To find out if chronic nerve compression could affect the peripheral nerve by acting as a "conditioning lesion", silicone tubes (internal diameter 0.8-1.6 mm) were placed round the sciatic or tibial nerves of adult rats for different time periods. After the period of compression the tubes were removed and a test crush lesion was made on the sciatic nerve in the thigh. Regeneration distances of the sensory nerve fibres were analysed by the pinch reflex test after a further three or six days. Compression of sciatic or tibial nerves induced a significant increase in outgrowth length compared with nerves subjected to mobilisation and crush lesion alone. All the tubes tested had a conditioning effect, but only tubes with a small internal diameter seemed to induce nerve fibre degeneration as assessed by immunocytochemistry. The results showed that chronic compression induced a regenerative response in the peripheral nerve. The mechanism by which this was accomplished remains obscure but it may involve both the neurons and the non-neuronal cells.

The medial collateral ligaments in the knee joints of 15 rabbits were replaced with expanded polytetrafluoroethylene (E-PTFE). The joints were not immobilised postoperatively, and their structure and function were evaluated after 12 months. Range of motion was equal in all groups. Stability of the knee joints and breaking strength of the ligaments were similar in the group in which the ligament had been reconstructed and in the sham operated control group (n = 8). The group in which the ligament had been severed and left to heal by formation of scar tissue (n = 7) had significantly reduced joint stability and the breaking strength of the medial collateral ligament was significantly less. The E-PTFE ligaments were well incorporated into the surrounding tissues. There were no adverse tissue reactions and the articular cartilage looked normal both macroscopically and microscopically. These results indicate that E-PTFE might be a useful substitute for damaged ligaments, at least in smaller joints like metacarpophalangeal and interphalangeal joints.

Reinnervation of the gastrocnemius and anterior tibial muscles was assessed by measurements of tetanic force after repair of sciatic nerves with Y-shaped or X-shaped silicone tubes in rats. The transsected proximal stump of either the tibial or the peroneal fascicle was introduced into the opening of a Y-shaped silicone tube, or both fascicles were introduced into an X-shaped tube. The distal tibial and peroneal fascicles were inserted into the distal outlets of the tubes leaving a gap of 4 mm between proximal and distal stumps. In the X-shaped tubes the proximal inserts were placed opposite or adjacent to their respective distal parts. Sixteen weeks later reinnervation was evaluated by measurements of tetanic force of the gastrocnemius and anterior tibial muscles after electrical stimulation of the fascicles. There was preferential reinnervation in both types of tubes. In Y-shaped tubes about 90% of the tetanic force could be recorded from both muscles after stimulation of the peroneal and tibial fascicles, respectively. Recovery was lower in the X-shaped tubes, amounting to about 75%. Contractions evoked by misrouted fibres were similar (roughly 40%) in both models. We conclude that motor axons preferentially, but not exclusively, selected a path to reinnervate their original target muscle.

To investigate the importance of nutritive environment in the healing of reconstructed ligaments, the morphology of sutured free patellar ligaments in synovial fluid of the contralateral knee joint, without re-establishment of microcirculation, was studied in rabbits. After two weeks (n = 6) and one (n = 6) and three (n = 5) months, the sutured ligament was removed from the joint and fibroblasts were seen growing into the suture gap. The ligaments were enveloped in a capsule of fibroblasts, which was more developed in those ligaments that were studied three months after operation. The collagen of the piece of ligament was disorganised at all time points, and tensile strength (n = 6) was low compared with non-sutured patellar ligament. Some ligaments disappeared or were partly attached to the synovial membrane and revascularised. The findings indicate that diffusion of nutrients may be important for the survival and healing of reconstructed ligaments, as the ligaments can heal in synovial fluid without re-establishment of the microcirculation.

The ulnar nerve of a 21-year old man was repaired at the wrist by a silicone chamber technique 10 days after a traumatic transection. A 3 mm gap was left between the nerve ends inside the chamber. At follow-up three years later, motor and sensory recovery was excellent. At exploration at that time a macroscopically normal nerve was found in the tube.

Gore-Tex (expanded Polytetrafluoroethylene, E-PTFE) was used to replace the distal pulleys on the proximal phalanges of 20 rabbits. Morphology and function of the reconstructed pulleys were evaluated at 12-20 weeks. The breaking strength of the E-PTFE pulley equalled that of a normal pulley. Range of motion, tendon excursion, and force of flexion were no different from those of normal pulleys. No adhesions between flexor tendons and synovial tendon sheaths or the E-PTFE pulleys could be detected. No adverse tissue reactions were seen. Fibroblast-like cells from the surrounding tissues had grown into the membrane. In other experiments, where the pulleys had been either removed or detached, local fibrosis and adhesions were seen, and the deep flexor tendons had ruptured. The results of the present study indicate that E-PTFE can be used as a biosynthetic replacement for damaged pulleys.

To study the effects of drying on regeneration, crush lesions were made on the sciatic nerve of 38 rats and the injured area was then air-dried for various periods of time (0-60 min). The regeneration distance of sensory nerve fibres was measured by the pinch reflex test three or six days later. Regeneration was significantly impaired by drying the nerve for 30 or 60 min, but shorter periods (10 min) also seemed to affect axonal outgrowth. Regeneration distances were increased in nerves that were subjected to drying and then allowed to recover for a week (conditioning interval) before the nerve was crushed. The results show that drying of a peripheral nerve is detrimental to nerve regeneration, and we suggest that nerves should not be exposed to air for more than a few minutes during operation without irrigation.

The hind limbs of anaesthetized rats were exposed to vibration trauma (81 Hz; amplitude peak to peak 0.50 mm) for 4 hours during 2 consecutive days. The animals were examined in groups of 4 immediately after the last exposure, and after 1, 2, 3, 5, 7, 10, 14 and 28 days. The Achilles tendons and the tendons of the anterior tibialis muscles were sampled and processed to demonstrate IGF-I immunoreactivity. In the normal Achilles tendon and in the tendon of the anterior tibial muscle, slight IGF-I immunoreactivity was seen in many of the long slender fibroblasts between the collagen bundles. A strong increase in the IGF-I immunoreactivity appeared in the anterior tibialis muscle tendon 3 days after the last vibration exposure. In addition, the tendon fibroblasts became hypertrophic. A similar but less striking increase in IGF-I immunoreactivity appeared in the Achilles tendon. The peak intensity and frequency of stained cells were achieved after 7 days for both tendons. The intensity then levelled off, and was normalized after 28 days. It is concluded that acute exposure to vibrations induces reactive changes in fibroblasts in tendons, which may reflect a change to a more active synthesising state, as a response to the vibration trauma. The transiently altered expression of IGF-I immunoreactivity forms a link in a chain of events regulating the functional activity level of fibroblasts in response to a trauma.

Gore-tex chambers were used to bridge a 6 mm gap between the proximal and distal nerve stumps of a rat sciatic nerve. The wall structure of these chambers is characterized by "nodes" interconnected by smaller fibrils. Chambers with internodal distances of 5, 10 and 30 microns were used. Some 30 microns chambers were coated from the outside with Gore-tex (0.2 micron internodal distance) and others were coated from the inside. Regeneration after 12 weeks, as evidenced by muscle action potential recordings and light microscopy, was successful regardless of what type of chamber had been used. The organization of the nerve structure varied among different chamber types. A well organized coaxial nerve structure with myelinated axons was observed if inner-coated chambers were used. In chambers that were not coated or in outer-coated chambers tissue completely filled the chambers, and myelinated axons were arranged in mini-fascicles surrounded by loose connective tissue.